Many communication devices operating on radio frequencies use crystal filters for improving channel selectivities. The crystals are housed in a manner which allows the crystal to vibrate yet firmly hold the crystal in place to prevent crystal damage or breakage. Crystal filters are often used in sets constituting multiple pole crystal filter systems. Many communication devices today use a four-pole crystal filter. A four-pole crystal filter can be constructed using a single filter blank and tapping four poles therefrom. Yet, the tapping of more than two-poles is expensive and not always reliable. Therefore, conventionally, a four-pole crystal filter comprises two two-pole crystal filters mounted on a printed circuit board and coupled in series. The printed circuit board real estate, though, is a valuable commodity, particularly if the communications device is portable making it desirable to minimize the size of the device. Furthermore, multiple crystal filters increases the device's component count and increases the opportunity for operational failure due to a component defect.
Thus, what is needed is a crystal filter package which would allow for mounting of two or more crystal filters in the same housing in a manner that would minimize the printed circuit board surface area occupied by the footprint of the multiple crystal blanks system, yet minimizing oscillatory interference between the crystals.